What’s Left?

What’s Left? lesson plan

Use Crayola Erasable Colored Pencils to draw a favorite food. Then erase it, piece by piece! Are you using fractions? Subtraction? Percentages? Proportions? Algebra? Division?

  • 1.

    Work with a small group of your classmates to choose a favorite food, such as pizza or an orange that can be divided into sections.

  • 2.

    On a large sheet of drawing paper, use Crayola Erasable Colored Pencils to draw the food. Draw lines to divide it evenly into sections or slices.

  • 3.

    Now, use the Erasable Colored Pencils to take turns erasing the food, section by section. Each time you erase a section, write at least one way to mathematically represent what you did. For example, if you start with 10 pieces, and erase 2, you might write 10 –2 = 8, or 2/10 = 1/5, or 20% is gone (or 80% is left). Use addition, subtraction, division, and multiplication to show your calculations. How many different ways can you express the action mathematically?

  • 4.

    Fill your paper with equations, fractions, and other mathematical statements each time you erase another piece.


  • Children work cooperatively to make decisions about their math project.
  • Students draw a favorite food and divide it into sections.
  • Children write mathematical statements to express how erasing sections of their work demonstrates subtraction, division, and other mathematical ideas.


  • Exchange drawings with another group. How many ways can you use math to express the equation they illustrated?
  • Undo a division problem you created by putting your food "back together" with an addition or multiplication equation.
  • Write a division equation for a friend. Now have your friend draw a picture to illustrate it.